Current cellular and wireless technology enables a built-in level of security protection through the use of a numeric code, sometimes referred to as a personal identification number (PIN). Such a feature enables subscribers to set security features such as phone lock and keypad lock to prevent unauthorized use or misuse of the subscriber device. In addition, modern cellular communication systems, such as Global System for Mobile Communication (GSM) use subscriber identity modules or SIM cards to personalize phone units into which the SIM cards are installed. Conventional SIM cards are smart cards that include user specific data. The data can, for example, define an international subscriber directory number (ISDN) or phone number, identity of the subscriber, memorized speed dialing numbers, unit features to which the subscriber has subscribed, and a security key.
The SIM card data or information can be protected using a SIM PIN security feature. An authentication process is performed during registration of a handset with the SIM card installed and the system or infrastructure and prior to permitting incoming and outgoing calls. Only if the authentication process is successful (user enters correct PIN) will the registration or call be allowed to take place.
To maintain system security, the SIM card is constructed so that its cryptographic security key cannot be read from or otherwise divulged by the SIM card. Thus, the SIM card allows the system to provide communication services only when authentication is successful, thus reducing the theft of communication services by unauthorized users. In such a conventional communications or cellular phone unit, barring a user's call can be obtrusive or obstructive when the user is prompted for a PIN each time an attempt is made to either make or receive a call. Additionally, if such a call barring feature is not enabled, the phone is open to fraudulent use if it is misplaced or stolen.
Therefore, what is needed is a method, and apparatus for dynamically controlling access to services, such as call services, in an unobtrusive manner.